Surfactants are well known materials which can be generally described as having a hydrophobic moiety and a hydrophilic group per molecule. A wide variety of these materials are known and are classified as anionic, cationic, nonionic and amphoteric. They are well known to be useful as emulsifiers, detergents, dispersants and solubilizing agents in the fields of cosmetics, textile treatment, industrial and personal cleaning preparations, corrosion inhibitors and the like.
In many surfactant containing compositions, such as personal cleaning preparations, mildness is a sought after characteristic. The amphoteric surfactants are particularly important in fulfilling that need. Amphoteric surfactants are compounds uniquely structured to function as cationic surfactants at acid pH and anionic surfactants at alkaline pH. At neutral pH, the amphoteric surfactants are neutral thus accounting for their mildness. These compounds are well known and some of these are shown in U.S. Pat. Nos. 3,941,817; 4,705,843; 2,781,354 and 2,773068 which are illustrative. Amphoteric surfactants are also known to be biodegradable, hence are ecologically compatible.
Surfactants generally are compounds having one hydrophilic group and one hydrophobic moiety. Recently, a group of compounds having two hydrophobic moieties and two hydrophilic groups have been introduced. These have become known as "Gemini surfactants" in the literature [(Chemtech, Mar. 1993, pp 30-33, --), and J.American Chemical Soc., 115, 10083-10090, (1993] and the references cited therein. Since their introduction, cationic and anionic "Gemini surfactants" have been disclosed. Other surfactant compounds having two hydrophilic groups and two hydrophobic moieties have been disclosed but not referred to as Gemini surfactants.
Due to the need for new and more effective and efficient surfactants, as well as the need for mild surfactants which are biologically compatible in an ecologically sensitive environment, effort has been made to develop a new class of compounds, which demonstrate improved surface-active properties that are further characterized as mild, and environmentally benign.